Few people have ever completed a thru-hike of the Grand Canyon, and now National Geographic explorers Kevin Fedarko and Pete McBride know why: The almost 800-mile hike quickly proved to be the most difficult undertaking of their lives. With no trail to follow, the two found themselves bushwhacking through dense brush and cacti, and moving up and down steep vertical terrain in scorching heat as they navigated their way through the canyon. Though they initially embarked on the hike as a way to raise public awareness of development issues threatening the iconic national park, the pair quickly found they had completely underestimated the difficulty of their journey and nearly quit in the first week. Join Fedarko and McBride as they comically recount their brutal adventure and shed light on the myriad of threats facing Grand Canyon National Park.

The National Geographic Live series brings thought-provoking presentations by today’s leading explorers, scientists, photographers, and performing artists right to you. Each presentation is filmed in front of a live audience at National Geographic headquarters in Washington, D.C.

- So what we're gonna do tonight, Kevin and I are gonna take you on an unusual and somewhat remarkable journey through a remarkable place, the Grand Canyon. But before we do that, we felt it's important to get a little bit of an idea of how we know each other, and I think that might reveal who we are a little bit.

- Yeah, and I should say that this is probably the moment, those of you who have come here tonight expecting to get a window into the sort of deep, symphonic emotional resonance that sets up between a professional photographer and a writer, this is the moment where I disabuse you of that delusion, because the pattern that unfolds between Pete and I basically consists of, it's extremely simple. Pete comes up with an apocalyptically bad idea. And in the course of attempting to convince him of what a bad idea this is and why we should not do it, he somehow, through a mysterious alchemy that involves intellectual seduction manages to drag me into the idea, and I find myself in yet another part of the world that I didn't want to be in in the first place.

- Alright, the first bad idea was to convince Kevin to join me in the Caucasus Mountains in the Republic of Georgia. Now, I grew up in the mountains, I love skiing, and this place is where the border patrol that patrols the Chechnya border operates on skis, and I was like, I want to follow these guys, I want to understand this part of the world, great idea.

- Would've been a great idea, two problems. These guys were very-- Very heavily armed. Second problem was that Pete didn't check the weather report. And the avalanches that resulted from the massive series of snowstorms that descended across the Black Sea and all of the Republic of Georgia shut the entire country down. And we spent the next week holed up in what should've been a hotel, except it was a bank... Eating food like this. Alright, so that wasn't, maybe not such a good idea. The next idea had less guns, higher chance of success, was to go to the north of Canada, to the Yukon, to one of the most remote areas up in the Arctic to follow the Porcupine Caribou Herd. And we had this thing dialed. We're gonna take the Firth River north on rafts, and we're gonna to time it, not only to see the greatest migration of the caribou herd moved across there, but we're gonna float with them as they travel.

- Yeah, and you'd think that two National Geographic journalists would be able to locate the Porcupine Caribou Herd. The largest collection of charismatic megafauna on the face of North America. But no, after two weeks of searching we did not manage to locate a single live animal.

- Alright, alright, so. Third strike, I figured, this one's gonna be a home run. How could this possibly go wrong, I convinced Kevin that there's this story on the south side of Mount Everest that is totally unusual and it's unique, and it's not about the circus of trying to get to the top of the mountain, it's about these guys that live, let me get that clicker to work, that live inside the Khumbu Icefall and basically build the route for everyone else to climb the mountain. These are the unsung heroes. And they do this remarkable job of building and engineering the route through this icefall that goes from 18,000 feet to 22,000 feet. This is their office, and most people don't know even who they are.

- And here's the problem, if your office looks like this, things like this tend to happen in it. A giant chunk of ice, about the size of an aircraft carrier may break off of a cornice, plummet 600 feet onto the top of the glacier and detonate, creating a giant cloud of vaporized ice crystals which hurdles towards you at about a hundred miles an hour. Now, at this point, I'm on the left side of this photograph running for my life-- And this other guy with us is doing the same thing, it's a testament to Pete's commitment to the art of photography that he managed to stand there and keep shooting.

- The reality is I didn't know what else to do, I thought that the avalanche was gonna basically snuff us out, so I figured I'd give some evidence of what happened to us. At this point, however, I basically realized that maybe that chasing these magazine stories all over the world is maybe not, maybe we need to change, maybe I'm ready to go home. And it had been a long journey and as you might detect, Kevin and I have a little bit of a different personality. I have a tendency, in part, because of what I do to look for the light in the world, I'm a photographer, I make films, I'm constantly looking for the bright side of things, I'd say I'm more optimistic. And Kevin, he sometimes thinks a little differently.

- Yeah, that would be an understatement. Look, I'm a dark person. The word itself is woven into my last name. And part of what that means is that I sort of specialize in and my ethos as a human being is rooted in the idea that it's necessary and important to take the worst possible interpretation of pretty much every situation. If the sun is shining, it is raining somewhere. Now it's a very sort of complex psychological matrix that I don't fully understand. The simplest way I can explain it to you is to put it into, well, let's just put it into terms of Winnie the Pooh. Basically, Pete is Tigger, and I'm Eeyore.

- So at this point, Tigger and Eeyore basically had a small breakup. I think we had a little fatigue of going in these misadventures together. We both returned home, I returned home to Colorado, this is basically my backyard river, and I decided to do something a little different, I was getting a little tired of chasing these short magazine stories, I wanted to do something a little longer and sink in my heels in a little bit more. So I followed my, what I call my backyard river, the Colorado River, I followed it from the mountains in the source of Colorado, basically 1,500 miles to try to understand, where does the western water, where does this lifeline that supports 40 million people in the Southwest, where does it go when it travels through this desert landscape, and what happens at the end, and does it reach the end. And to my amazement, the Colorado River doesn't. It gets dried up in this place right here. The Sea of Cortez a hundred miles shy of the sea. We dried it up roughly two decades ago, it ran to the sea for six million years, and we turned it into basically this desert wasteland. And what I realized at this point is that there are a lot of stories around rivers and water, that's the arteries of our planet, so to speak, that are getting untold. And so I became very committed, I think, to try to document these stories on some level.

- And I may have had some notion of your commitment had I not decided that I had temporarily stopped speaking to Pete at this point, and so I was completely unaware that he was engaged in this very sort of comprehensive project that was focused on, as it turns out, the very same thing that I was focused on, it's just the only difference was that I had my eye on one particular section of the Colorado River. I'm talking about the most storied and legendary section of all, the 277 miles that runs through the Grand Canyon in Northern Arizona. The section of river that is defined by exceptional sections of gorgeous light and beautiful, beautiful tranquility, punctuated by moments of unholy chaos that are known as rapids. And it's inside of those rapids that some of the real sort of savagery unfolds inside the river and the river really gives you an idea of how powerful it truly is and what it's capable of doing to you.

- [Pete] That's you paddling, right?

- That was not me paddling, but there's some truth to it because I'd become obsessed, I'd become obsessed with the world of the river, and I'd become obsessed with the particular story attached to a particular man. This guy's name is Kenton Grua, he's a legendary Grand Canyon river guide, in 1983, as Peter Gwin mentioned a few minutes ago, he set the speed record, the standing speed record of the fastest boat in history to race though the Grand Canyon, but Kenton Grua had achieved something six years earlier that was arguably an even greater accomplishment. It was an incredibly bold vision. The idea was, what he wanted to do, was he wanted to start at the eastern end of the Grand Canyon and walk on foot all the way through to the western terminus, where the canyon goes through something called the Grand Wash Cliffs and ends. Now he was following in the footsteps of the man that Peter just mentioned, John Wesley Powell, the one-armed Civil War veteran, who accomplished one of the most extraordinary acts in the history of American exploration in the summer of 1869 when he led an expedition consisting of 10 men in four boats, including himself, down to the Colorado River. I want you to think for a moment about the 108 years, that gap between 1869, John Wesley Powell's pioneering river voyage, 1977, Kenton Grua's first traverse through the Grand Canyon. And I want you to ask yourself what that gap says about the brokenness and brutality and complexity of this landscape. It suggests that it is a place that does not invite and indeed, ferociously resists human intrusion.

- So I came back to this broken landscape three years ago. I was invited by the national park to do a talk about my project on the river itself. And I suddenly, I had this kind of epiphany, I hiked down into the canyon, and I had this idea.

- Please don't be seduced by the rainbow. Worst idea in the history of journalism.

- Alright, well that's Eeyore saying that, but fortunately, National Geographic agreed that this might be a good idea, actually. And they agreed to sponsor us, and eventually I was able to convince Kevin to follow in the footsteps of Kenton Grua. I'm gonna be honest. I'm not sure I really like hiking that much. With a heavy pack, no trail, and no guarantee of water, it's hard, stressful and very slow. Sure, hiking can lead to some zen-like moments, but not so much if you're lost, really tired and dehydrated. Yet there's something about the Grand Canyon and its rocky, secret world. It is alluring, magical even. So in the fall of 2015, my friend and author Kevin Fedarko and I set out to walk the entirety of the Grand Canyon from east to west. In order to understand the insanity of this venture, you first have to know a little bit about this place. In stretches, it is 18 miles wide and over a mile deep, so deep, in fact, you could stack five Empire State Buildings, one on top of the other inside. It is 277 miles long, if you're floating the Colorado River. But on foot, by the time you've gone up and back down the numerous side canyons, it's more like 700 miles. Oh yeah, and for more most of it, there's no trail. How far are we going?

- I don't think we've gone five miles yet.

- This is really hard hiking, it kinda demoralizes you a little bit.

- As a result, more people have stood on the surface of the moon than have completed a continuous thru-hike of the Grand Canyon. Unlike those intrepid few, Kevin and I decided to do a sectional version, chipping off a hundred to 150-mile chunks at a time. Just 30 hikers have completed sectional lines through the park. And for some, it took them decades to finish. Tragically, others have perished attempting it. Kevin and I would be the first journalists ever to tackle this hiking lunacy. We plan to complete our mission over a year, watching the seasons change and teaming up with hardened canyon veterans to help us find our way and our legs. But beyond that challenge, something else drew us on this quest. Many claim the Grand Canyon is facing an unprecedented array of pressures from all four points on the compass. Development projects are poised to change the integrity of perhaps the most monumental landscape in America. And we believe walking the park might give us a unique perspective on this secret world and what's at stake to be lost between the river and the rim. So like I said, I think I was quickly reminded how I don't like hiking that much. So the real purpose of this project from the beginning, from the genesis of it, was to actually shine a spotlight on what's happening in the park as it approaches its hundredth birthday. And the reality of what's happening, and we're gonna walk you through some of these issues, as it is getting pressure from all four points on the compass, from all sides, east, west, north and south. And we figured that this walk would, basically we could walk through it, the walk would be the backbone to talk about this. We did know when we started that alright, this was maybe a place we knew the river better than we knew the area between the river and the rim and so we needed some help. So this guy wearing the Star-Spangled Banner gaiters, Rich Rudow is one of the gurus of the canyon, he spent over 700 nights below the canyon. When we started I asked him what the hell were these Star-Spangled Banner thingies. They're maybe the most important little item you can have if you're a Grand Canyon hiker, they're these gaiters that keep the ferocious, angry cactus and everything else that wants to get into your feet, ankles on, of course, we didn't know what they were, so we were a little clueless on some level, but we basically latched onto these guys. He agreed to let us follow them on their 57-day thru-hike. They were gonna start hiking in September of 2015 and not stop.

- This is basically what a special forces Grand Canyon A-Team looks like. The level of experience that's captured in this photograph extends back into decades. These are men who spent an enormous amount of time, they've invested time and energy learning this environment. This is what it looks like through their eyes when two yahoos from National Geographic show up. Prepare to tie themselves onto the back of their bumper like a couple of tin cans, which raises an interesting question, why in the world would these guys allow us to come along? The answer's interesting, and it says something about them. Their commitment to the canyon and their concern over what's happening to this environment is so great that basically they were aware of the fact that we were capable of telling a story that they thought was incredibly important, and they were equally aware of the fact that this environment is so difficult physically that we would be incapable of moving through it without their assistance. And so we embarked on this journey with them starting off through the first part of the canyon, a section known as Marble Canyon.

- And since Kevin and I had, we'd been down the river a few times, we both rode the river successfully, unsuccessfully, I, however, had this idyllic view that we would do basically a raft trip in hiking boots. We'd be walking and we'd enjoy the tangerine light and maybe we'd have a little swim after six hours of hiking, Kevin might pen some poetry, I might do some time-lapse photography. Wrong. We quickly started realizing, alright, it was a little more complex, we knew it was gonna be hard, but when you start looking at the 22 layers of rock inside the Grand Canyon and the endless number of tributaries that puncture this landscape and that you have to walk around and leave, you quickly start realizing like, this is no raft trip on foot.

- Right, and that's just the first of a whole series of problems that start coming at you like a fire hose. And all of them are rooted, really, in one basic fact, which is that there's no trail, right? And so what that means among so many other things is that every single step that you take in this landscape is a careful negotiation between you and the terrain itself. It's an act also that's complicated and made infinitely more difficult by the heat, by your level of energy and by the fact that you are carrying on your back 50 pounds and so when you have to perform a dynamic and energy-draining full body move in order to maintain your balance, you do that over and over again. Minute after minute, hour after hour. It's so destructive to the body that by the end of the first day, you basically end up looking like this. Pete, where's Tigger at this point, huh?

- Yeah, I think day one, day two, Tigger crawled into a dark cave with Eeyore. Pretty much wanted to just crawl under the cave permanently at this point. This looks like a nice, idyllic scene, I was expecting this, sit around and tell stories under the spray of stars at night. Au contraire, this is September, late September, an unusual heat wave rolled in. I just don't do well with heat. It's 110 degrees consistently throughout the day. This is about 98 degrees, we're trying to sleep, this is a furnace. And this is a total nightmare. By day three or day four, I'm starting to feel really weird and sick, I'm not thinking clearly. Day four or five, I realized we are completely in over our heads. I'm not eating anymore, Kevin's having a hard time with his ankles. We're in a bad spot.

- We're in a bad spot, and most of it really is related to the heat. It's difficult to overstate just how difficult, just how awful 105 degrees is. But to give you an idea, one of the things it did, was so hot that the heat was literally melting the bottoms of our shoes. And so the story of the impact that that process had was written in our feet for the first couple of days. But there was another story unfolding invisibly inside of our body that was less evident. By the third day, I had descended into what seemed to me to be a bottomless well of despair and death. And as bad as that may sound what was happening inside of Pete was far more alarming, I think.

- So by day three I'm starting to have this weird sensation, I'm not thinking clearly, and I'm starting to get body cramps. I got to a point where my tongue cramped and my hand, I was like, this is weird. Something ain't right, so I must be dehydrated, I wasn't peeing all day. So I started consuming a lot of water, I'm drinking salts and swim, too, but basically, I sweat a lot, I sweated so much, I sweated all of my natural sodium system out, and I became hyponatremic, this is the opposite of dehydration, you deplete your salt levels so low in your body that you start to vomit water, you can go unconscious, go into seizures and then a coma. I was, at this point, feeling like I was headed towards unconsciousness, we realized we gotta evacuate. So we hike out, we call in a friend. This great guy JP comes in, brings us in salty stuff, I'm drinking soy sauce desperately, and we're able to hike out a hike that should've taken three hours in normal temperatures, under normal conditions, it took us about seven hours, we limp out and crawl back to Flagstaff, where I get, really, the first glance of Kevin's ankles and realize that they're totally blown out and sprained. And at this point, we're basically staring down the barrel of failure. And I'm embarrassed on one level, these amazing thru-hikers have us let join them and we've screwed their plan up, they kept going, but we delayed them a little bit. I've brought Kevin in on this mission where he's miserably depressed at this point. And then what am I gonna tell National Geographic, my friend Sadie Quarrier, the editor who's here somewhere, what am I gonna tell her, we're just total clowns and how are we gonna pull this out because not only was I messed up, I was sick, but I was frankly scared to go back into this place. It was daunting. It had really, really beaten it out of me.

- Yeah and I felt the same way, no surprise. Which brings me to kind of a difficult moment right now, because as it turns out, we were on the threshold of a turning point in this journey. And it therefore forces me to say something positive, because much to my surprise and unbeknownst to Pete, a miracle was about to occur. And that miracle had to do with the fact that Flagstaff is a very small community, but it sits on the edge of the Grand Canyon, and there's a very tiny but incredibly passionate group of people who are deeply committed to the Grand Canyon. And because it's a small town, word travels very, very quickly. So word got out that these two idiots from National Geographic-- Had basically tailspinned out of control, retreated back to Flagstaff with their tails between their legs and were considering abandoning this very important story about the Grand Canyon, and so what these people did was they decided that they were gonna rally. They showed up my house, whole group of them. And over the next two to three weeks, they redid our entire program. They redialed our gear, they re-engineered our food system, and they basically embarked on a process that resulted in a Grand Canyon hiking makeover that was designed to get us back into the canyon, back in gear and enable us to resume the mission which was to get our butts continuing downstream.

- And that we did. They brought us back in, and one challenge for me is that usually when you do these assignments for National Geographic, you're really afraid that if you go in with one camera and that camera breaks, you can't be like, well I didn't have a camera. But it is so challenging that they convinced me that I had to drop all my extra lenses, all of my extra cameras, all of my extra batteries, I did the whole thing on one camera and one lens. And then they brought us back into the canyon and showed us ways to get through following the sheep trails. Don't be near the river, follow, look for the hoof prints, look for the little black pellets. They brought us through ancient ruins, they brought us through some recent impacts, you can see some old markings that people have carved their names a hundred years ago. And they basically got us back on track to our initial mission.

Few people have ever completed a thru-hike of the Grand Canyon, and now National Geographic explorers Kevin Fedarko and Pete McBride know why: The almost 800-mile hike quickly proved to be the most difficult undertaking of their lives. With no trail to follow, the two found themselves bushwhacking through dense brush and cacti, and moving up and down steep vertical terrain in scorching heat as they navigated their way through the canyon. Though they initially embarked on the hike as a way to raise public awareness of development issues threatening the iconic national park, the pair quickly found they had completely underestimated the difficulty of their journey and nearly quit in the first week. Join Fedarko and McBride as they comically recount their brutal adventure and shed light on the myriad of threats facing Grand Canyon National Park.

The National Geographic Live series brings thought-provoking presentations by today’s leading explorers, scientists, photographers, and performing artists right to you. Each presentation is filmed in front of a live audience at National Geographic headquarters in Washington, D.C.